import { type ReactNode, useState } from "react";
import { useTranslation } from "react-i18next";
import { keepPreviousData, useQuery } from "@tanstack/react-query";
import { qk } from "../lib/queryKeys";
import { SlidersHorizontal } from "lucide-react";
import { api, type FeedFilters, type Tag, type TagCategory } from "../lib/api";
import { defaultLayout, type PanelLayout } from "../lib/panelLayout";
import { useDebounced } from "../lib/useDebounced";
import { useActiveFilters } from "../lib/useActiveFilters";
import TagManager from "./TagManager";
import SavedViewsPopover from "./SavedViewsPopover";
import { useSavedViews } from "./SavedViewsProvider";
import FilterRail from "./FilterRail";
import { type PanelItem } from "./PanelGroups";
import { type MediaSourceKind } from "../lib/mediaSource";
import ChannelPicker from "./ChannelPicker";
import DateFilterSelect from "./DateFilterSelect";
import Combobox, { type ComboboxOption } from "./Combobox";
import { useFeedFilters, useFeedFiltersActions } from "./FeedFiltersProvider";
import { useChannelsActions } from "./ChannelsProvider";
import { useMe } from "../lib/useMe";

// Filter ids; display labels resolved at render time via t("sidebar.sort.<id>") etc.
const DATE_PRESETS: { days: number; key: string }[] = [
  { days: 1, key: "24h" },
  { days: 7, key: "1week" },
  { days: 14, key: "2weeks" },
  { days: 30, key: "1month" },
  { days: 90, key: "3months" },
  { days: 180, key: "6months" },
  { days: 365, key: "1year" },
  { days: 730, key: "2years" },
  { days: 1825, key: "5years" },
];

export default function Sidebar({
  layout,
  setLayout,
  collapsed,
  onToggleCollapse,
}: {
  layout: PanelLayout;
  setLayout: (l: PanelLayout) => void;
  collapsed: boolean;
  onToggleCollapse: () => void;
}) {
  const { t } = useTranslation();
  const isDemo = useMe().is_demo;
  const { openModal } = useSavedViews();
  const filters = useFeedFilters();
  const { setFilters } = useFeedFiltersActions();
  // "Focus this channel in the manager" (from the tag manager here) lives in ChannelsProvider.
  const { focusChannel: onFocusChannel } = useChannelsActions();
  const tagsQuery = useQuery({ queryKey: qk.tags(), queryFn: api.tags });
  const tags = tagsQuery.data ?? [];

  // Live per-tag channel counts for the current filter context. Debounce the search term so
  // typing doesn't refire facets per keystroke, and keep previous counts during a refetch.
  const facetFilters: FeedFilters = { ...filters, q: useDebounced(filters.q, 300) };
  // Shared with the feed's count (same key + filters -> React Query dedupes to one request): the feed
  // reads `.count`, this reads `.facets` (PERF-13, replaces the separate facets query).
  const summaryQuery = useQuery({
    queryKey: qk.feedSummary(facetFilters),
    queryFn: () => api.feedSummary(facetFilters),
    staleTime: 30_000,
    placeholderData: keepPreviousData,
  });
  const facetsReady = !!summaryQuery.data;
  const facetCounts = summaryQuery.data?.facets ?? {};
  const chipCount = (tag: Tag): number =>
    facetsReady ? (facetCounts[String(tag.id)] ?? 0) : tag.channel_count;
  const visibleChips = (list: Tag[]): Tag[] => {
    const shown = facetsReady
      ? list.filter((tg) => chipCount(tg) > 0 || filters.tags.includes(tg.id))
      : list;
    return [...shown].sort((a, b) => chipCount(b) - chipCount(a) || a.name.localeCompare(b.name));
  };

  const languages = tags.filter((t) => t.category === "language");
  const topics = tags.filter((t) => t.category === "topic");
  const userTags = tags.filter((t) => !t.system);
  const [tagManagerOpen, setTagManagerOpen] = useState(false);
  // This rail's media source (the feed). Names the abstraction the feed and Plex rails share; drives
  // the panel layout key. `FilterRail` owns the customize `editing` state now.
  const source: MediaSourceKind = "feed";

  // The language/topic/tags sections all write into the one `filters.tags` list, so each combobox owns
  // only its own slice: its selection replaces the ids that belong to its list, leaving the others.
  const tagOption = (tg: Tag): ComboboxOption => ({
    value: String(tg.id),
    label: tg.name,
    count: chipCount(tg),
  });
  const selectedIn = (list: Tag[]): string[] =>
    filters.tags.filter((id) => list.some((tg) => tg.id === id)).map(String);
  function setTagSelection(list: Tag[], next: string[]) {
    const inList = new Set(list.map((tg) => tg.id));
    setFilters({
      ...filters,
      tags: [...filters.tags.filter((id) => !inList.has(id)), ...next.map(Number)],
    });
  }
  // Each tag category (language/topic/other) has its OWN any/all match, set from its combobox footer.
  const setTagMode = (category: TagCategory, mode: "or" | "and") =>
    setFilters({ ...filters, tagModes: { ...filters.tagModes, [category]: mode } });

  // The badge counts exactly what the chip row above the feed shows — same list, so they can't
  // disagree about what's applied.
  const activeCount = useActiveFilters(filters, setFilters).length;

  const available: Record<string, boolean> = {
    date: true,
    channel: true,
    language: languages.length > 0,
    topic: topics.length > 0,
    tags: userTags.length > 0,
  };

  function widgetBody(id: string): ReactNode {
    switch (id) {
      case "channel":
        return <ChannelPicker filters={filters} setFilters={setFilters} />;
      case "date":
        return (
          <DateFilterSelect filters={filters} setFilters={setFilters} presets={DATE_PRESETS} />
        );
      case "language": {
        return (
          <Combobox
            label={t("sidebar.widget.language")}
            options={visibleChips(languages).map(tagOption)}
            selected={selectedIn(languages)}
            onChange={(next) => setTagSelection(languages, next)}
            emptyText={t("sidebar.noMatchingTags")}
            matchMode={filters.tagModes.language}
            onMatchModeChange={(m) => setTagMode("language", m)}
          />
        );
      }
      case "topic": {
        return (
          <Combobox
            label={t("sidebar.widget.topic")}
            options={visibleChips(topics).map(tagOption)}
            selected={selectedIn(topics)}
            onChange={(next) => setTagSelection(topics, next)}
            emptyText={t("sidebar.noMatchingTags")}
            matchMode={filters.tagModes.topic}
            onMatchModeChange={(m) => setTagMode("topic", m)}
          />
        );
      }
      case "tags": {
        // The widget's own "Manage" trigger is its title (see the PanelItem onTitleClick below), so the
        // body is just the picker.
        return (
          <Combobox
            label={t("sidebar.widget.tags")}
            options={visibleChips(userTags).map(tagOption)}
            selected={selectedIn(userTags)}
            onChange={(next) => setTagSelection(userTags, next)}
            emptyText={t("sidebar.noMatchingTags")}
            matchMode={filters.tagModes.other}
            onMatchModeChange={(m) => setTagMode("other", m)}
          />
        );
      }
      default:
        return null;
    }
  }

  // Group ids come from the shared default order (panelLayout) so there's one source of truth;
  // the actual render order is the user's saved layout (PanelGroups orders by it).
  const items: PanelItem[] = defaultLayout(source)
    .order.filter((id) => available[id])
    .map((id) => ({
      id,
      title: t("sidebar.widget." + id),
      body: widgetBody(id),
      // The widgets aren't collapsible, so a widget's title can act as its own trigger: "Your tags"
      // opens the tag manager (replacing the old inline Manage button).
      onTitleClick: id === "tags" ? () => setTagManagerOpen(true) : undefined,
      titleActionLabel: id === "tags" ? t("sidebar.manageTags") : undefined,
    }));

  return (
    <FilterRail
      kind={source}
      title={t("sidebar.filters")}
      icon={<SlidersHorizontal className="w-4 h-4" />}
      count={activeCount}
      collapsed={collapsed}
      onToggleCollapse={onToggleCollapse}
      layout={layout}
      setLayout={setLayout}
      items={items}
      // The feed widgets are simple label + control rows, not collapsible islands.
      collapsible={false}
      // Saved ("personal") views: the header icon opens a quick-pick popover, the title opens the
      // full manager modal. Hidden for the demo account (no per-user views). Feed rail only.
      iconExpanded={
        !isDemo && source === "feed" ? (
          <SavedViewsPopover trigger={<SlidersHorizontal className="w-4 h-4" />} />
        ) : undefined
      }
      onTitleClick={!isDemo && source === "feed" ? openModal : undefined}
      titleActionLabel={!isDemo && source === "feed" ? t("views.manageTitle") : undefined}
    >
      {tagManagerOpen && (
        <TagManager onClose={() => setTagManagerOpen(false)} onFocusChannel={onFocusChannel} />
      )}
    </FilterRail>
  );
}